bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[Philipp Stephani]

Assuming /tmp/[ab].py are existing files.

emacs -Q -f server-start /:/tmp/a.py

Then:

emacsclient --create-frame --eval '(ediff "/tmp/a.py" "/tmp/b.py")'

will result un an error:

*ERROR*: Wrong type argument: arrayp, nil

Backtrace is

Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
  file-name-non-special(verify-visited-file-modtime #<buffer a.py>)
  verify-visited-file-modtime(#<buffer a.py>)
  apply(verify-visited-file-modtime #<buffer a.py>)
  tramp-run-real-handler(verify-visited-file-modtime (#<buffer a.py>))
  tramp-file-name-handler(verify-visited-file-modtime #<buffer a.py>)
  verify-visited-file-modtime(#<buffer a.py>)
  find-file-noselect("/tmp/a.py")
  ediff-find-file(file-A buf-A ediff-last-dir-A startup-hooks)
  ediff-files-internal("/tmp/a.py" "/tmp/b.py" nil nil ediff-files)
  ediff("/tmp/a.py" "/tmp/b.py")
  eval((ediff "/tmp/a.py" "/tmp/b.py"))
  server-eval-and-print("(ediff \"/tmp/a.py\" \"/tmp/b.py\")" #<process server <3>>)
  (more uninteresting frames)



In GNU Emacs 26.0.50 (build 10, x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2017-03-03 built on localhost
Repository revision: 244de7b0ed3bb23e700c9edef51e413602d8720a
Windowing system distributor 'The X.Org Foundation', version 11.0.11501000
System Description:	Ubuntu 14.04 LTS

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --enable-checking --enable-check-lisp-object-type
 --with-modules 'CFLAGS=-O0 -ggdb3''

Configured features:
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TOOLKIT_SCROLL_BARS GTK3 X11 MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
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faces cus-face macroexp files text-properties overlay sha1 md5 base64
format env code-pages mule custom widget hashtable-print-readable
backquote inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 96397 9305)
 (symbols 48 20188 1)
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 (strings 32 17669 3597)
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bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[Philipp Stephani]

[-- Attachment #1.1: Type: text/plain, Size: 1207 bytes --]

Philipp Stephani <p.stephani2@gmail.com> schrieb am Fr., 3. März 2017 um
14:58 Uhr:

>
> Assuming /tmp/[ab].py are existing files.
>
> emacs -Q -f server-start /:/tmp/a.py
>
> Then:
>
> emacsclient --create-frame --eval '(ediff "/tmp/a.py" "/tmp/b.py")'
>
> will result un an error:
>
> *ERROR*: Wrong type argument: arrayp, nil
>
> Backtrace is
>
> Debugger entered--Lisp error: (wrong-type-argument arrayp nil)
>   file-name-non-special(verify-visited-file-modtime #<buffer a.py>)
>   verify-visited-file-modtime(#<buffer a.py>)
>   apply(verify-visited-file-modtime #<buffer a.py>)
>   tramp-run-real-handler(verify-visited-file-modtime (#<buffer a.py>))
>   tramp-file-name-handler(verify-visited-file-modtime #<buffer a.py>)
>   verify-visited-file-modtime(#<buffer a.py>)
>   find-file-noselect("/tmp/a.py")
>   ediff-find-file(file-A buf-A ediff-last-dir-A startup-hooks)
>   ediff-files-internal("/tmp/a.py" "/tmp/b.py" nil nil ediff-files)
>   ediff("/tmp/a.py" "/tmp/b.py")
>   eval((ediff "/tmp/a.py" "/tmp/b.py"))
>   server-eval-and-print("(ediff \"/tmp/a.py\" \"/tmp/b.py\")" #<process
> server <3>>)
>   (more uninteresting frames)
>
>
Patch is attached.

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From 9e5d1d09a4597885b1fc40feec6dbf64cf1e29cd Mon Sep 17 00:00:00 2001
From: Philipp Stephani <phst@google.com>
Date: Sat, 22 Apr 2017 00:12:23 +0200
Subject: [PATCH] Fix quoted files for 'verify-visited-file-modtime'

Fixes Bug#25951.

* lisp/files.el (file-name-non-special): Set the file name for the
correct buffer.

* test/lisp/files-tests.el (files-tests--file-name-non-special--buffers):
Add unit test.
---
 lisp/files.el            | 12 ++++++++++--
 test/lisp/files-tests.el | 42 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/lisp/files.el b/lisp/files.el
index 6848818cad..64843287e5 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -6987,8 +6987,16 @@ file-name-non-special
            (when (and visit buffer-file-name)
              (setq buffer-file-name (concat "/:" buffer-file-name))))))
       (`unquote-then-quote
-       (let ((buffer-file-name (substring buffer-file-name 2)))
-         (apply operation arguments)))
+       (let ((buffer (current-buffer)))
+         ;; `unquote-then-quote' is only used for the
+         ;; `verify-visited-file-modtime' action, which takes a buffer
+         ;; as only optional argument.
+         (with-current-buffer (or (car arguments) buffer)
+           (let ((buffer-file-name (substring buffer-file-name 2)))
+             ;; Make sure to hide the temporary buffer change from the
+             ;; underlying operation.
+             (with-current-buffer buffer
+               (apply operation arguments))))))
       (_
        (apply operation arguments)))))
 
diff --git a/test/lisp/files-tests.el b/test/lisp/files-tests.el
index 80bbeb1bc5..ed66533d48 100644
--- a/test/lisp/files-tests.el
+++ b/test/lisp/files-tests.el
@@ -1,4 +1,4 @@
-;;; files-tests.el --- tests for files.el.
+;;; files-tests.el --- tests for files.el.  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012-2017 Free Software Foundation, Inc.
 
@@ -20,6 +20,7 @@
 ;;; Code:
 
 (require 'ert)
+(require 'nadvice)
 
 ;; Set to t if the local variable was set, `query' if the query was
 ;; triggered.
@@ -251,5 +252,44 @@ files-test-bug-18141-file
                       (start-file-process "foo" nil "true"))))
   (should (eq (let ((default-directory "/:/")) (shell-command "true")) 0)))
 
+(ert-deftest files-tests--file-name-non-special--buffers ()
+  "Check that Bug#25951 is fixed.
+We call `verify-visited-file-modtime' on a buffer visiting a file
+with a quoted name.  We use two different variants: first with
+the buffer current and a nil argument, second passing the buffer
+object explicitly.  In both cases no error should be raised and
+the `file-name-non-special' handler for quoted file names should
+be invoked with the right arguments."
+  (with-temp-buffer
+    (let* ((buffer-file-name "/:/tmp/bug25951.txt")
+           (buffer-visiting-file (current-buffer))
+           (actual-args ())
+           (log (lambda (&rest args) (push args actual-args))))
+      (set-visited-file-modtime '(1 2 3 4))
+      (should (equal (find-file-name-handler buffer-file-name
+                                             #'verify-visited-file-modtime)
+                     #'file-name-non-special))
+      (advice-add #'file-name-non-special :before log)
+      (unwind-protect
+          (progn
+            (should (stringp buffer-file-name))
+            ;; This should call the file name handler with the right
+            ;; buffer and not signal an error.  The file doesn't
+            ;; actually exist, so this should return nil.
+            (should-not (verify-visited-file-modtime))
+            (with-temp-buffer
+              (should (stringp (buffer-file-name buffer-visiting-file)))
+              ;; This should call the file name handler with the right
+              ;; buffer and not signal an error.  The file doesn't
+              ;; actually exist, so this should return nil.
+              (should-not (verify-visited-file-modtime buffer-visiting-file)))))
+      (advice-remove #'file-name-non-special 'bug25951)
+      ;; Verify that the handler was actually called.  We called
+      ;; `verify-visited-file-modtime' twice, so both calls should be
+      ;; recorded in reverse order.
+      (should (equal actual-args
+                     `((verify-visited-file-modtime ,buffer-visiting-file)
+                       (verify-visited-file-modtime nil)))))))
+
 (provide 'files-tests)
 ;;; files-tests.el ends here
-- 
2.12.2

bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[npostavs]

Philipp Stephani <p.stephani2@gmail.com> writes:

> +       (let ((buffer (current-buffer)))
> +         ;; `unquote-then-quote' is only used for the
> +         ;; `verify-visited-file-modtime' action, which takes a buffer
> +         ;; as only optional argument.
> +         (with-current-buffer (or (car arguments) buffer)
> +           (let ((buffer-file-name (substring buffer-file-name 2)))
> +             ;; Make sure to hide the temporary buffer change from the
> +             ;; underlying operation.
> +             (with-current-buffer buffer
> +               (apply operation arguments))))))

I think this could be simplified by using the buffer-file-name function:

    ;; `unquote-then-quote' is only used for the
    ;; `verify-visited-file-modtime' action, which takes a buffer
    ;; as only optional argument.
    (let ((buffer-file-name
           (substring (buffer-file-name (car arguments)) 2)))
      (apply operation arguments))

bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[Philipp Stephani]

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<npostavs@users.sourceforge.net> schrieb am Sa., 22. Apr. 2017 um 00:48 Uhr:

> Philipp Stephani <p.stephani2@gmail.com> writes:
>
> > +       (let ((buffer (current-buffer)))
> > +         ;; `unquote-then-quote' is only used for the
> > +         ;; `verify-visited-file-modtime' action, which takes a buffer
> > +         ;; as only optional argument.
> > +         (with-current-buffer (or (car arguments) buffer)
> > +           (let ((buffer-file-name (substring buffer-file-name 2)))
> > +             ;; Make sure to hide the temporary buffer change from the
> > +             ;; underlying operation.
> > +             (with-current-buffer buffer
> > +               (apply operation arguments))))))
>
> I think this could be simplified by using the buffer-file-name function:
>
>     ;; `unquote-then-quote' is only used for the
>     ;; `verify-visited-file-modtime' action, which takes a buffer
>     ;; as only optional argument.
>     (let ((buffer-file-name
>            (substring (buffer-file-name (car arguments)) 2)))
>       (apply operation arguments))
>

That's not the same, it will set the file name of the wrong buffer.

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bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[npostavs]

Philipp Stephani <p.stephani2@gmail.com> writes:

> <npostavs@users.sourceforge.net> schrieb am Sa., 22. Apr. 2017 um 00:48 Uhr:
>
>> Philipp Stephani <p.stephani2@gmail.com> writes:
>>
>> > +       (let ((buffer (current-buffer)))
>> > +         ;; `unquote-then-quote' is only used for the
>> > +         ;; `verify-visited-file-modtime' action, which takes a buffer
>> > +         ;; as only optional argument.
>> > +         (with-current-buffer (or (car arguments) buffer)
>> > +           (let ((buffer-file-name (substring buffer-file-name 2)))
>> > +             ;; Make sure to hide the temporary buffer change from the
>> > +             ;; underlying operation.
>> > +             (with-current-buffer buffer
>> > +               (apply operation arguments))))))
>>
>> I think this could be simplified by using the buffer-file-name function:
>>
>>     (let ((buffer-file-name
>>            (substring (buffer-file-name (car arguments)) 2)))
>>       (apply operation arguments))
>>
>
> That's not the same, it will set the file name of the wrong buffer.

Oh, I think I get it now.  It could be written like this, right?

    (cl-letf* ((buf (or (car arguments) (current-buffer)))
               ((buffer-local-value buffer-file-name buf)
                (substring (buffer-file-name buf) 2)))
      (apply operation arguments))

bug#25951: 26.0.50; Error when ediffing files that are visited using quoted file names

[Philipp Stephani]

[-- Attachment #1: Type: text/plain, Size: 1553 bytes --]

<npostavs@users.sourceforge.net> schrieb am Sa., 22. Apr. 2017 um 22:31 Uhr:

> Philipp Stephani <p.stephani2@gmail.com> writes:
>
> > <npostavs@users.sourceforge.net> schrieb am Sa., 22. Apr. 2017 um 00:48
> Uhr:
> >
> >> Philipp Stephani <p.stephani2@gmail.com> writes:
> >>
> >> > +       (let ((buffer (current-buffer)))
> >> > +         ;; `unquote-then-quote' is only used for the
> >> > +         ;; `verify-visited-file-modtime' action, which takes a
> buffer
> >> > +         ;; as only optional argument.
> >> > +         (with-current-buffer (or (car arguments) buffer)
> >> > +           (let ((buffer-file-name (substring buffer-file-name 2)))
> >> > +             ;; Make sure to hide the temporary buffer change from
> the
> >> > +             ;; underlying operation.
> >> > +             (with-current-buffer buffer
> >> > +               (apply operation arguments))))))
> >>
> >> I think this could be simplified by using the buffer-file-name function:
> >>
> >>     (let ((buffer-file-name
> >>            (substring (buffer-file-name (car arguments)) 2)))
> >>       (apply operation arguments))
> >>
> >
> > That's not the same, it will set the file name of the wrong buffer.
>
> Oh, I think I get it now.  It could be written like this, right?
>
>     (cl-letf* ((buf (or (car arguments) (current-buffer)))
>                ((buffer-local-value buffer-file-name buf)
>                 (substring (buffer-file-name buf) 2)))
>       (apply operation arguments))
>

Yes, that should work, thanks. Will send a new patch in a second.

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bug#25951: [PATCH] Fix quoted files for 'verify-visited-file-modtime'

[Philipp Stephani]

Fixes Bug#25951.

* lisp/files.el (file-name-non-special): Set the file name for the
correct buffer.

* test/lisp/files-tests.el (files-tests--file-name-non-special--buffers):
Add unit test.
---
 lisp/files.el            |  9 ++++++++-
 test/lisp/files-tests.el | 42 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/lisp/files.el b/lisp/files.el
index 6848818cad..2e9ab1aad1 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -28,6 +28,8 @@
 
 ;;; Code:
 
+(eval-when-compile (require 'cl-lib))
+
 (defvar font-lock-keywords)
 
 (defgroup backup nil
@@ -6987,7 +6989,12 @@ file-name-non-special
            (when (and visit buffer-file-name)
              (setq buffer-file-name (concat "/:" buffer-file-name))))))
       (`unquote-then-quote
-       (let ((buffer-file-name (substring buffer-file-name 2)))
+       (cl-letf* ((buffer (or (car arguments) (current-buffer)))
+                  ((buffer-local-value 'buffer-file-name buffer)
+                   (substring (buffer-file-name buffer) 2)))
+         ;; `unquote-then-quote' is only used for the
+         ;; `verify-visited-file-modtime' action, which takes a buffer
+         ;; as only optional argument.
          (apply operation arguments)))
       (_
        (apply operation arguments)))))
diff --git a/test/lisp/files-tests.el b/test/lisp/files-tests.el
index 80bbeb1bc5..9c633198f1 100644
--- a/test/lisp/files-tests.el
+++ b/test/lisp/files-tests.el
@@ -1,4 +1,4 @@
-;;; files-tests.el --- tests for files.el.
+;;; files-tests.el --- tests for files.el.  -*- lexical-binding: t; -*-
 
 ;; Copyright (C) 2012-2017 Free Software Foundation, Inc.
 
@@ -20,6 +20,7 @@
 ;;; Code:
 
 (require 'ert)
+(require 'nadvice)
 
 ;; Set to t if the local variable was set, `query' if the query was
 ;; triggered.
@@ -251,5 +252,44 @@ files-test-bug-18141-file
                       (start-file-process "foo" nil "true"))))
   (should (eq (let ((default-directory "/:/")) (shell-command "true")) 0)))
 
+(ert-deftest files-tests--file-name-non-special--buffers ()
+  "Check that Bug#25951 is fixed.
+We call `verify-visited-file-modtime' on a buffer visiting a file
+with a quoted name.  We use two different variants: first with
+the buffer current and a nil argument, second passing the buffer
+object explicitly.  In both cases no error should be raised and
+the `file-name-non-special' handler for quoted file names should
+be invoked with the right arguments."
+  (with-temp-buffer
+    (let* ((buffer-file-name "/:/tmp/bug25951.txt")
+           (buffer-visiting-file (current-buffer))
+           (actual-args ())
+           (log (lambda (&rest args) (push args actual-args))))
+      (set-visited-file-modtime '(1 2 3 4))
+      (should (equal (find-file-name-handler buffer-file-name
+                                             #'verify-visited-file-modtime)
+                     #'file-name-non-special))
+      (advice-add #'file-name-non-special :before log)
+      (unwind-protect
+          (progn
+            (should (stringp buffer-file-name))
+            ;; This should call the file name handler with the right
+            ;; buffer and not signal an error.  The file doesn't
+            ;; actually exist, so this should return nil.
+            (should-not (verify-visited-file-modtime))
+            (with-temp-buffer
+              (should (stringp (buffer-file-name buffer-visiting-file)))
+              ;; This should call the file name handler with the right
+              ;; buffer and not signal an error.  The file doesn't
+              ;; actually exist, so this should return nil.
+              (should-not (verify-visited-file-modtime buffer-visiting-file))))
+        (advice-remove #'file-name-non-special 'bug25951))
+      ;; Verify that the handler was actually called.  We called
+      ;; `verify-visited-file-modtime' twice, so both calls should be
+      ;; recorded in reverse order.
+      (should (equal actual-args
+                     `((verify-visited-file-modtime ,buffer-visiting-file)
+                       (verify-visited-file-modtime nil)))))))
+
 (provide 'files-tests)
 ;;; files-tests.el ends here
-- 
2.12.2